Red Geta

Shirokawa Amazake

According to the Ryorimonogatari, an early 17th century cookbook, shirokawa amazake is a sweet and white fermented beverage made from polished rice. It is a form of sake called namazake (raw or un-pasteurized) dating to the Heian-jidai (794 – 1185 CE) in Japan. The characteristic milky color and texture come from the minimal filtering, often done through hemp cloth. Sake has been known in Japan since its introduction from China by 200 BCE in the Jomon-jidai (4000 – 200 BCE) (Yoshikawa et al., 1995).

The method for brewing kuchikami no sake, a 3rd century CE forerunner of shirokawa amazake, is a parallel fermentation process. According to an early Chinese travel diary, initial fermentation began when cooked rice was chewed and spat into an open vat, by virgins no less (Ishige, 1990). Amylase, an enzyme present in human saliva, begins to saccharify starches into the simple carbohydrate, amylose. Cooked rice is added to the open vat, and wild yeast begins the conversion of the amylose to alcohol (Atkinson, 1881). This produces a thick and chewy mash.

The method of brewing shirokawa amazake is similar, but by historical times the Japanese had adopted the Chinese technique of using koji. The Aspergillus oryzae in koji produces enzymes which convert the complex carbohydrates in rice into simple sugars. Yeast, as in the earlier process, then converts the sugars to alcohol. Koji was most likely discovered accidentally, as it grows well on mochi, steamed and mashed glutinous rice (Ishige, 1990).

Though shirokawa amazake should not be classified as a wine, as it involves multiple fermentation processes, it is not truly a beer or ale. The fermentation processes occur simultaneously and not in succession.

This shirokawa amazake was brewed from medium-grain rice (Tokio Daigaku, 1881). Four-hundred grams of cooked rice was combined with 5 grams of koji and left to ferment at approximately 75 degrees Fahrenheit for 40 hours until filaments of the fungus were visible. This mixture, known as koji-ko, was added to 1500 grams more of cooked rice and 4 liters of water in a standard carboy. To mimic the secondary fermentation provided by wild yeast, 5 grams of champagne yeast was added to the mixture (Mutsuo, 1996). I used champagne yeast because the woman at the brewery supply store said it would least affect the taste. According to Wikipedia, spoilage was common among milky sake especially during the summer months. Therefore, I decided to add 5 grams of citric acid as a preservative. (Do not add citric acid, or at least add much, much less than 5 grams.) I believe that in period, sake was brewed in completely open wooden vats. I covered my mixture with a double-layer of paper toweling to prevent contamination. This mixture was kept for 2 weeks at room temperature and stirred daily. The mixture was strained through cotton muslin, again in lieu of hemp cloth, and bottled (Mutsuo, 1996).

This shirokawa amazake was brewed with a combination of period materials (rice, koji) and modern materials (champagne yeast, citric acid), but with a period technique of primary and secondary fermentation in an open container. I learned later that amazake takes less time to brew, as stated in the Ryorimonogatari, but this technique was based on a submission to a modern, online brewery database.